Nervous system

Question 1

What does the nervous system do?

Answer 1

coordinate behaviour
respond to surroundings

Question 1

Use of neurons

Answer 1

carry electrical impulses

Question 2

Neurones adaptations

Answer 2

many dendrites: connect to more, pass more msg
myelin sheath: insulates impulses, speeds up impulse conduction

Question 3

what are synapses, how do they work

Answer 3

gap between neurones
neurotransmitters are released to pass electrical impulses in a chemical way
post- receptors synapse membrane doesn’t allow backflow of impulses
electric current triggered and is transmission is continued

Question 4

possible problems with synapses

Answer 4

interfered by other imitating or blocking chemicals
v drugs to deal

Question 5

3 types of neurones

Answer 5

sensory, relay, motor

Question 6

components and uses of CNS

Answer 6

brain + spinal cord
take in sensory info, instruct body to work

Question 7

flow chart from stimulus to response

Answer 7

stimulus → receptor cells → sensory neurone → CNS (relay neurone) → motor neurone → effector → respons

Question 8

spine isnt the same as spinal chord

Question 9

Question 10

types of receptors

Answer 10

eyes (light), ears (sound), nose (chemical), pain, pressure (KE / chem), temperature (thermal)

Question 11

what’s a reflex arc

Answer 11

it’s the nerve pathway that underlies our unconscious reflexes
rapid and automatic, involuntary
avoid danger, protect

Question 12

how is a reflex arc different from a normal reaction

Answer 12

a reflex arc doesn’t involve the brain, only spinal cord

Question 13

What is homeostasis

Answer 13

Maintenance of a constant internal environment
Body temp & water content

Question 14

What does co-ordinated response require

Answer 14

Stimulus, receptor, effector

Question 15

Function of lens

Answer 15

Change shape to bend light onto retina

Question 16

Lens vs cornea in terms of light refraction

Answer 16

Cornea: refracts light in the same amount, x flexible
Lens: adjust amount of light refracted

Question 17

Function of optic nerve

Answer 17

Neurones to carry impulse

Question 18

Suspensions ligament isn’t a muscle

Question 19

What’s special about the blind spot

Answer 19

There aren’t any cones or rods, x image forms

Question 20

What is the fovea (spelling!)

Answer 20

Place where light should bend to

Question 21

What are the 2 types of cells the retina contain

Answer 21

1. Cone cells: works in bright light, sensitive to red, green, blue, found in fovea only
2. Rod cells: works in dim light, only black and white, found all over the retina

Question 22

Answer 22

A: vitreous humour
B: lens
C: cornea
D: pupil
E: iris (control pupil size)
F: sclera
G: optic nerves
H: choroid (spelling!)
I: aqueous humour
J: ciliary muscle
K: suspensory ligament (fibre)
L: fovea
M: blind spot

Question 23

Answer 23

A: vitreous humour
B: lens
C: cornea
D: pupil
E: iris (control pupil size)
F: sclera
G: optic nerves
H: choroid (spelling!)
I: aqueous humour
J: ciliary muscle
K: suspensory ligament (fibre)
L: fovea
M: blind spot

Question 24

Circulatory muscles and radial muscles are found in the iris,
Which one is the inner muscle

Answer 24

Circulatory muscle is the inner one

Question 25

Iris reflex under bright light

Answer 25

Circulatory muscles contract
Radial muscles relax
Constricted / smaller pupil to prevent too much light entering which may bleach the eye

Question 26

Iris reflex under dim light

Answer 26

Circular muscles relax, radial muscles contract
Dilated pupil, allow more light in

Question 27

Where are the suspensory ligament and ciliary muscles located

Answer 27

Suspensory ligaments (fibres) and attached to the lens and the ciliary muscles

Question 28

Focusing on near object

Answer 28

Ciliary muscle contract, suspensory ligament slackens
Fat lens, curve, more refraction

Question 29

Focusing on distant objs

Answer 29

Ciliary muscles relax, suspensory ligament becomes taut
Thin lens, slight light refraction

Question 30

Suspensory ligament can’t contract